Method of circulating through a reciprocating downhole tubing pump and a reciprocating downhole tubing pump

ABSTRACT

A method of circulating through a reciprocating downhole tubing pump and a reciprocating downhole tubing pump. The reciprocating downhole tubing pump has a standing valve assembly and a travelling valve. The method involves displacing and disabling, without removing, the standing ball valve assembly and the travelling valve. This can be done with pins which knock the balls out of position or by enclosing the balls in cages which can be mechanically moved out of position with linkages. With the standing ball valve assembly and the travelling valve disabled, circulation can occur through the reciprocating downhole tubing pump. This has a number of advantages, such as removal of blockages due to sand accumulation.

FIELD OF THE INVENTION

The present invention relates to a method of circulating through a reciprocating downhole tubing pump and a reciprocating downhole tubing pump which has been modified in accordance with the teachings of the method.

BACKGROUND OF THE INVENTION

A reciprocating downhole tubing pump has a standing ball valve and a travelling ball valve positioned downhole. Blockages periodically occur in the tubing string. The blockages are usually the result of an accumulation of sand below the standing ball valve of such downhole tubing pumps, although the blockages can occur above or in the downhole tubing pump. When this occurs, the entire tubing string and downhole tubing pump are pulled from the well using a service rig. The blockage is then removed from the tubing at surface. Before the production string is run back in, it is necessary to bail or circulate to remove sand accumulations down hole in order to reposition the down hole tubing pump at the desired depth.

SUMMARY OF THE INVENTION

What is required is a method of circulating through the standing ball valve assembly and travelling valve of a downhole tubing pump, without having to pull the tubing string and the downhole tubing pump from the well.

According to one aspect of the present invention there is provided a method of circulating through a reciprocating downhole tubing pump which has a standing ball valve and a travelling ball valve positioned downhole. A first step involves providing first means for mechanically displacing and disabling, without removing, a ball from a ball seat on the travelling ball valve. A second step involve providing second means for mechanically displacing and disabling, without removing, a ball from a ball seat on the standing valve assembly. A third step involves activating the first means to prevent the ball from engaging the ball seat on the travelling ball valve and the second means to prevent the ball from engaging the ball seat on the standing ball valve assembly and circulating fluids through both the travelling ball valve and the standing ball valve assembly.

According to another aspect of the present invention there is provided a reciprocating downhole tubing pump which includes a barrel and a piston axially movable along the barrel. A travelling ball valve is carried by the piston. The travelling valve has a ball seat which receives a ball. First means are provided for mechanically displacing and disabling, without removing, the ball from the ball seat on the travelling ball valve. A standing ball valve assembly is positioned within the barrel. The standing ball valve assembly includes a ball seat which receives a ball. Second means are provided for mechanically displacing and disabling, without removing, the ball from the ball seat on the standing valve assembly. Means are provided for activating the first means to prevent the ball from engaging the ball seat on the travelling ball valve and the second means to prevent the ball from engaging the ball seat on the standing ball valve assembly, such that a circulation of fluids can occur through both the travelling ball valve and the standing ball valve assembly.

The above described method sets forth the broad aspects of the present invention. Once the inventive concept is understood, there may be different ways of putting it into effect. As will be hereinafter described, in a preferred embodiment an upstanding first pin is secured on top of the standing ball valve assembly. This first pin is in axial alignment with a ball seat, which receives a ball on the travelling ball valve. A rigid pivot linkage is provided having a first end and a second end. The first end is secured to the ball cage with a fulcrum positioned between the first end and the second end, such that when a downward force is exerted on the second end of the pivot linkage, the pivot linkage pivots about the fulcrum lifting a ball cage from an operative position to a circulating position in which the raised ball cage lifts the ball on the standing ball valve assembly from the ball seat. An upstanding second pin is secured to the second end of the pivot linkage extending above the standing ball valve assembly adjacent to the first pin. When the travelling ball valve is lower onto the standing ball valve assembly, the first pin extends through the valve seat to prevent the ball from engaging the ball seat on the travelling ball valve and the second pin acts upon the pivot linkage to pivot the ball cage to the circulating position to prevent the ball from engaging the ball seat on the standing ball valve assembly. This permits an unfettered circulation of fluids through both the travelling ball valve and the standing ball valve assembly.

In another preferred embodiment, the standing ball valve is axially movable along the barrel with axial travel being limited by an underlying axial stop. An upstanding first pin is secured on top of the standing ball valve assembly. The first pin is in axial alignment with the ball seat on the travelling ball valve assembly. An upstanding second pin is mounted below the standing ball valve assembly. The second pin protrudes above the axial stop in axial alignment with the ball seat on the standing ball valve assembly. A spring is positioned between the standing ball valve and the axial stop. The spring biases the standing ball valve assembly into an operative position spaced above the second pin. Upon the travelling ball valve engaging the standing ball valve assembly and a compressive force being exerted upon the spring, the standing ball valve assembly is moved to a circulating position with the first pin preventing the ball from engaging the ball seat on the travelling ball valve and the second pin preventing the ball from engaging the ball seat on the standing ball valve assembly. This permits a circulation of fluids through both the travelling ball valve and the standing ball valve assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein:

FIG. 1 is a side elevation view, in section, of a reciprocating downhole tubing pump constructed in accordance with the teachings of the present method with the standing ball valve assembly and the travelling valve in an operative position.

FIG. 2 is a side elevation view, in section, of the reciprocating downhole tubing pump illustrated in FIG. 1, with the standing ball valve assembly and the travelling valve in a circulating position.

FIG. 3 is a detailed side elevation view, in section, of an offset transfer ball cage and pivot linkage constructed in accordance with the teachings of the present method.

FIG. 4 is a side elevation view, in section, of a reciprocating downhole tubing pump constructed in accordance with the teachings of the present method with the standing ball valve assembly and the travelling valve in an operative position.

FIG. 5 is a side elevation view, in section, of the reciprocating downhole tubing pump illustrated in FIG. 4, with the standing ball valve assembly and the travelling valve in a circulating position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment, a reciprocating downhole tubing pump generally identified by reference numeral 10, will now be described with reference to FIGS. 1 through 5.

Structure and Relationship of Parts:

Referring to FIG. 1, reciprocating downhole tubing pump 10 has a barrel 12. A piston 13 transports a travelling ball valve 14 having a first ball seat 16 and a first ball 18 is axially movable along barrel 12. A standing ball valve assembly 20 having a second ball seat 22 and a second ball 24 is positioned within barrel 12. Second ball 24 is confined within a ball cage 26. An upstanding first pin 28, in axial alignment with first ball seat 16 and first ball 18 of travelling ball valve 14, is secured on top of standing ball valve assembly 20. Standing ball valve assembly 20 is further adapted with a rigid pivot linkage 30, an offset transfer body 31 and a screen 32. Referring to FIG. 3, rigid pivot linkage 30 has a first end 33 and a second end 34. A fulcrum 36 is positioned between first end 33 and second end 34. When a downward force 38 is exerted on second end 34, linkage 30 pivots about fulcrum 36, lifting ball cage 26 and second ball 24 from an operative position to a circulating position. An upstanding second pin 40 is secured to second end 34 of linkage 30 and extends above standing ball valve assembly 20 adjacent to first pin 28. Referring to FIG. 2, when piston 13 transports travelling ball valve 14 onto standing ball valve assembly 20, first pin 28 extends through first valve seat 16, preventing first ball 18 from engaging first ball seat 16 in travelling ball valve 14. Upon contact with travelling ball valve 14, second pin 40 acts upon pivot linkage 30, pivoting ball cage 26 to a circulating position by preventing second ball 24 from engaging second ball seat 22 of standing ball valve assembly 20, allowing an unfettered circulation of fluids through both travelling ball valve 14 and standing ball valve assembly 20.

Referring now to FIG. 4, there is shown another embodiment of the reciprocating downhole tubing pump 10. As in the embodiment shown in FIGS. 1 to 3, reciprocating downhole tubing pump 10 has barrel 12, travelling ball valve 14 having first ball seat 16 which receives first ball 18, and standing ball valve assembly 20 having second ball seat 22 which receives second ball 24. In this embodiment, axial travel of standing ball valve assembly 20 is limited by an underlying axial stop 42. Upstanding first pin 28 is secured on top of standing ball valve assembly 20. First pin 28 is in axial alignment with first ball seat 16 on travelling ball valve 14. An upstanding second pin 44, positioned below standing ball valve assembly 20, protrudes above axial stop 42 and is in axial alignment with second ball seat 22 on standing ball valve assembly 20. A spring 46 is positioned between standing ball valve assembly 20 and axial stop 42. A spring sealer 48 seals spring 46 at axial stop 42. Spring 46 biases standing ball valve assembly 20 in an operative position spaced above second pin 44. Referring to FIG. 2, where travelling ball valve 14 contacts standing ball valve assembly 20 and a compressive force 50 is exerted upon spring 46, standing ball valve assembly 20 is moved to a circulating position with first pin 28 preventing first ball 18 from engaging first ball seat 16 on travelling ball valve 14. Further, second pin 44 prevents second ball 24 from engaging second ball seat 22 on standing ball valve assembly 20, thereby permitting an unfettered circulation of fluids 52 through both travelling ball valve 14 and standing ball valve assembly 20.

Operation:

The use and operation of the first embodiment of reciprocating downhole tubing pump 10 in accordance with the teachings of the preferred method, will now be described with reference to FIGS. 1 through 3. Referring to FIG. 1, where a blockage of sand or other impediment occurs below standing ball valve assembly 20, piston 13 with travelling ball valve 14 is positioned within barrel 12 above standing ball valve assembly 20 as provided. Referring to FIG. 3, as piston 13 with travelling ball valve 14 is lowered and contact is made with standing ball valve assembly 20, upstanding second pin 40 exerts downward force 38 onto second end 34 of rigid pivot linkage 30, lifting ball cage 26 and unseating second ball 24 from second seat 22 and opening standing ball valve 20 for circulation. Referring to FIG. 2, similarly, upstanding first pin 28 unseats first ball 18, opening travelling ball valve 14 for circulation. As both valves are in a circulating position, any blockages may then be cleared by the flow of fluid. The blockage is then removed from the tubing at surface. Very little extra preparation is required to get the well into production again. This concept saves the need of removing the reciprocating downhole tubing pump, circulating or running a sand bailer, and then reinstalling the reciprocating downhole tubing pump.

The use and operation of the second embodiment will now be described with reference to FIGS. 3 and 4. Referring to FIG. 3, where a blockage of sand or other impediment occurs below standing ball valve assembly 20, travelling ball valve 14 is lowered onto standing ball valve assembly 20 and a compressive force 50 is exerted upon spring 46 to move standing ball valve assembly 20 to the circulating position as shown in FIG. 4. Referring to FIG. 4, first pin 28 prevents first ball 18 from engaging first ball seat 16 on travelling ball valve 14, and second pin 44 prevents second ball 24 from engaging second ball seat 22 on standing ball valve assembly 20. It should be noted that compressive force 50 may be provided by the weight of a tubing string or by fluid under pressure.

Variations:

It should be noted that the dislodging and disabling of the ball on the travelling valve and the ball on the standing valve can be done in either order or simultaneously. In field trials the ball on the standing valve was dislodged and disabled first. The reason for this was that the ball on the standing valve is not subjected to the same fluid pressure, as the ball on the travelling valve is generally holding the fluid weight in the tubing.

It is desirable to place a screen below the standing ball valve assembly. The screen serves two valuable functions. When fluid is flowing in an upward direction through the standing ball valve assembly, it prevents debris which cannot be pumped from entering and acts as a vortex to break up fluid composition prior to entering pump. When fluid is flowing in a downward direction, it acts as a spray nozzle.

Advantages:

There are a number of advantages obtainable through the use of the method and apparatus, as described above:

-   1. At the present time hours of rig time are spent during pump     installation to circulate fluids to clean out sand fill or using     bailers to bail sand accumulations to clean up the cellar. With the     present invention, one can circulate the reciprocating downhole     tubing pump into the desired landing depth. One way this may be done     is by pinning the pump with shear screws. Once in position, an     anchor can be set and a force can be exerted upon the pump to shear     the shear screws to open up the pump stroke. -   2. The ability to circulate enables you to pump fluid into the     formation, to assist in opening up the perforations or the     formation. -   3. If the formation is tight, you could circulate the entire hole     over by sending fluid down tubing and up and out the casing. -   4. If a blockage should occur in the pump, above the pump or below     the pump, the blockage can be addressed by direct circulation of     fluids which flushes the tubing string of blockages. While blockages     mainly occur below the pump, they sometimes occur elsewhere in the     tubing string. -   5. The described invention can be used in conjunction with other     tools, such as a scraper, a casing swabbing device or drill out     equipment to accomplished several tasks in one operation.

In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention as hereinafter defined in the claims. 

1. A method of circulating through a reciprocating downhole tubing pump which has a standing ball valve and a travelling ball valve positioned downhole, comprising the steps of: providing first means for mechanically displacing and disabling, without removing, a ball from a ball seat on the travelling ball valve; providing second means for mechanically displacing and disabling, without removing, a ball from a ball seat on the standing valve assembly; and activating the first means to prevent the ball from engaging the ball seat on the travelling ball valve and the second means to prevent the ball from engaging the ball seat on the standing ball valve assembly and circulating fluids through both the travelling ball valve and the standing ball valve assembly.
 2. A reciprocating downhole tubing pump, comprising: a barrel; a piston axially movable along the barrel; a travelling ball valve carried by the piston, the travelling valve having a ball seat which receives a ball; a first means for mechanically displacing and disabling, without removing, the ball from the ball seat on the travelling ball valve; a standing ball valve assembly positioned within the barrel, the standing ball valve assembly including a ball seat which receives a ball; a second means for mechanically displacing and disabling, without removing, the ball from the ball seat on the standing valve assembly; and means for activating the first means to prevent the ball from engaging the ball seat on the travelling ball valve and the second means to prevent the ball from engaging the ball seat on the standing ball valve assembly, such that a circulation of fluids can occur through both the travelling ball valve and the standing ball valve assembly.
 3. A method of circulating through a reciprocating downhole tubing pump which has a standing ball valve and a travelling ball valve positioned downhole, comprising the steps of: providing displacing means on top of the standing ball valve assembly for displacing a ball from a ball seat on the travelling ball valve when the travelling ball valve is lowered onto the standing ball valve assembly; providing a linkage for displacing a ball from a ball seat on the standing valve assembly, the linkage being engaged to displace the ball when the travelling ball valve is lowered onto the standing ball valve assembly; and lowering the travelling ball valve onto the standing ball valve assembly, such that the displacing means extends through the valve seat to prevent the ball from engaging the ball seat on the travelling ball valve and the travelling valve acts upon the linkage to prevent the ball from engaging the ball seat on the standing ball valve assembly, thereby permitting an unfettered circulation of fluids through both the travelling ball valve and the standing ball valve assembly.
 4. A method of circulating through a reciprocating downhole tubing pump which has a standing ball valve and a travelling ball valve positioned downhole, comprising the steps of: providing a standing ball valve assembly that has: an upstanding first pin secured on top of the standing ball valve assembly, the first pin being in axial alignment with a ball seat which receives a ball on the travelling ball valve; a ball seat which receives a ball, the ball being confined within a ball cage; a pivot linkage adapted to pivot the ball cage from an operative position to a circulating position in which the ball cage is raised and the ball on the standing ball valve assembly is lifted by the ball cage off the ball seat; and lowering the travelling ball valve onto the standing ball valve assembly, such that the first pin extends through the valve seat to prevent the ball from engaging the ball seat on the travelling ball valve and the travelling valve acts upon the pivot linkage to pivot the ball cage to the circulating position to prevent the ball from engaging the ball seat on the standing ball valve assembly, thereby permitting an unfettered circulation of fluids through both the travelling ball valve and the standing ball valve assembly.
 5. A method of circulating through a reciprocating downhole tubing pump which has a standing ball valve and a travelling ball valve positioned downhole, comprising the steps of: providing a standing ball valve assembly that has: an upstanding first pin secured on top of the standing ball valve assembly, the first pin being in axial alignment with a ball seat which receives a ball on the travelling ball valve; a ball seat which receives a ball, the ball being confined within a ball cage; a rigid pivot linkage having a first end and a second end, the first end being secured to the ball cage with a fulcrum positioned between the first end and the second end, such that when a downward force is exerted on the second end of the pivot linkage, the pivot linkage pivots about the fulcrum lifting the ball cage from an operative position to a circulating position in which the raised ball cage lifts the ball on the standing ball valve assembly from the ball seat; an upstanding second pin secured to the second end of the pivot linkage and extending above the standing ball valve assembly adjacent to the first pin; and lowering the travelling ball valve onto the standing ball valve assembly, such that the first pin extends through the valve seat to prevent the ball from engaging the ball seat on the travelling ball valve and the second pin acts upon the pivot linkage to pivot the ball cage to the circulating position to prevent the ball from engaging the ball seat on the standing ball valve assembly, thereby permitting an unfettered circulation of fluids through both the travelling ball valve and the standing ball valve assembly.
 6. A reciprocating downhole tubing pump, comprising: a barrel; a travelling ball valve axially movable along the barrel, the travelling valve having a ball seat which receives a ball; a standing ball valve assembly positioned within the barrel, the standing ball valve assembly including a ball seat which receives a ball, the ball being confined within a ball cage; an upstanding first pin secured on top of the standing ball valve assembly, the first pin being in axial alignment with a ball seat which receives a ball on the travelling ball valve; a rigid pivot linkage having a first end and a second end, the first end being secured to the ball cage with a fulcrum positioned between the first end and the second end, such that when a downward force is exerted on the second end of the pivot linkage, the pivot linkage pivots about the fulcrum lifting the ball cage from an operative position to a circulating position in which the raised ball cage lifts the ball on the standing ball valve assembly from the ball seat; and an upstanding second pin secured to the second end of the pivot linkage and extending above the standing ball valve assembly adjacent to the first pin, such that when the travelling ball valve is lowered onto the standing ball valve assembly the first pin extends through the valve seat to prevent the ball from engaging the ball seat on the travelling ball valve and the second pin acts upon the pivot linkage to pivot the ball cage to the circulating position to prevent the ball from engaging the ball seat on the standing ball valve assembly, thereby permitting an unfettered circulation of fluids through both the travelling ball valve and the standing ball valve assembly.
 7. The reciprocating downhole tubing pump as defined in claim 6, wherein a screen is positioned below the standing ball valve assembly.
 8. A method of circulating through a reciprocating downhole tubing pump which has a standing ball valve and a travelling ball valve positioned downhole, comprising the steps of: providing a standing ball valve assembly that is axially movable along a barrel of the downhole tubing pump with axial travel being limited by an underlying axial stop, an upstanding first pin being secured on top of the standing ball valve assembly, the first pin being in axial alignment with a ball seat which receives a ball on the travelling ball valve; securing an upstanding second pin below the standing ball valve assembly, the second pin protruding above the axial stop in axial alignment with a ball seat which receives a ball on the standing ball valve assembly; positioning a spring between the standing ball valve and the axial stop, the spring biasing the standing ball valve assembly into an operative position spaced above the second pin, upon the spring being compressed the standing ball valve assembly assuming a circulating position with the second pin preventing the ball from engaging the ball seat on the standing ball valve assembly; and lowering the travelling ball valve onto the standing ball valve assembly and exerting a compressive force upon the spring to move the standing ball valve assembly to the circulating position, such that the first pin prevents the ball from engaging the ball seat on the travelling ball valve and the second pin prevents the ball from engaging the ball seat on the standing ball valve assembly, thereby permitting an unfettered circulation of fluids through both the travelling ball valve and the standing ball valve assembly.
 9. The method as defined in claim 8, the compressive force being provided by a weight of a tubing string.
 10. The method as defined in claim 8, the compressive force being provided by fluid under pressure.
 11. A reciprocating downhole tubing pump, comprising: a barrel; a travelling ball valve axially movable along the barrel, the travelling valve having a ball seat which receives a ball; a standing ball valve assembly axially movable along the barrel with axial travel being limited by an underlying axial stop, the standing ball valve assembly having a ball seat which receives a ball; an upstanding first pin secured on top of the standing ball valve assembly, the first pin being in axial alignment with the ball seat on the standing ball valve assembly; an upstanding second pin below the standing ball valve assembly, the second pin protruding above the axial stop in axial alignment with the ball seat on the standing ball valve assembly; and a spring between the standing ball valve and the axial stop, the spring biasing the standing ball valve assembly into an operative position spaced above the second pin, such that, upon the travelling ball valve contacting the standing ball valve assembly and a compressive force being exerted upon the spring, the standing ball valve assembly is moved to a circulating position with the first pin preventing the ball from engaging the ball seat on the travelling ball valve and the second pin preventing the ball from engaging the ball seat on the standing ball valve assembly, thereby permitting an unfettered circulation of fluids through both the travelling ball valve and the standing ball valve assembly. 